Fluid discharge vibration damping strips for acoustic protection of aircraft turbomachine fan casing

Abstract

An acoustic protection device for a fan casing of an aircraft turbomachine, including an acoustic protection panel forming a ferrule sector centered on a center axis, and one or more vibration damping strips pressed on a first side to an external surface of the panel and on a second side to an internal surface of the casing, each damping strip including two opposite edges each including an upstream end and a downstream end spaced from each other along a direction of the center axis. At least one of both opposite edges of at least one of the damping strips is shaped such that liquid present on this edge can flow by gravity towards either or both of its upstream and downstream ends.

The invention claimed is: 
     
       1. An acoustic protection device for a fan casing of an aircraft turbomachine, comprising:
 an acoustic protection panel forming a ferrule sector centered on a center axis same as a longitudinal axis of the fan casing; 
 one or more vibration damping strips pressed on a first side to an external surface of the acoustic protection panel and being pressed on a second side to an internal surface of the fan casing, each damping strip including two opposite edges each including an upstream end and a downstream end spaced from each other along the direction of the center axis, 
 wherein at least one of the two opposite edges of at least one of the damping strips is shaped such that liquid present in this edge can flow by gravity toward either or both of its upstream and downstream ends. 
 
     
     
       2. The device according to  claim 1 , wherein at least one of the two opposite edges of at least one of the damping strips includes at least one portion tilted with respect to the center axis, such that liquid present on this portion can flow by gravity toward either or both of its upstream and downstream ends. 
     
     
       3. The device according to  claim 2 , wherein at least one of the two opposite edges of at least one of the damping strips includes two successive portions in a direction of the center axis, each of both portions being tilted along the center axis such that liquid present on each of both portions can flow by gravity toward the upstream end and the downstream end respectively. 
     
     
       4. The device according to  claim 3 , wherein an angle formed between the two edge portions is between 1° and 15°, or between 1° and 3°. 
     
     
       5. The device according to  claim 3 , wherein the two edge portions are a same length. 
     
     
       6. The device according to  claim 1 , wherein at least one of the damping strips is shaped to be mountable on the acoustic panel at two reversed mounting positions, wherein the positions of the two opposite edges are respectively reversed, and in each of both mounting positions, at least one of both opposite edges of the damping strip is shaped such that liquid present on this edge can flow by gravity toward either of both of its upstream and downstream ends. 
     
     
       7. The device according to  claim 1 , wherein at least one of the damping strips has a first plane of symmetry arranged between the two opposite edges. 
     
     
       8. The device according to  claim 7 , wherein at least one of the damping strips has a second plane of symmetry passing through both opposite edges. 
     
     
       9. The device according to  claim 1 , wherein each damping strip is made of an elastomeric material. 
     
     
       10. An aircraft turbomachine front part comprising a fan casing with an internal surface coated with at least one acoustic protection device according to  claim 1 .